a) Field of the Invention
The present invention relates to an endoscopic length-measuring tool adapted to pass through a forceps channel to measure a size of a diseased part or the like within a body cavity.
b) Description of Related Art
The present inventor previously proposed a related endoscopic length-measuring tool, as disclosed in Japanese Utility Model Kokoku Publication No. Hei. 6-44401. The proposed length-measuring tool is advantageous over other available endoscopic length-measuring tools because it is simple in structure, and can be used in combination with various endoscopes.
This related length-measuring tool has two splits formed in a portion at a predetermined distance near a front end of a flexible sheath. The splits extend in a direction perpendicular to an axial direction of the sheath. The portion in which the two splits are formed is protruded from the front end of an endoscope, and bent into a T-shape with the aid of the two splits, so that a scale on the bent portion (i.e., a length-measuring section) can be observed through an endoscope.
The proposed length-measuring tool, which uses the T-shaped bent portion as a length-measuring section has a drawback. That is, since the length-measuring section is in the form of a single bar, if a rotational direction of the length-measuring tool relative to the endoscope is not appropriate, the length-measuring section will not be within observation visual field of the endoscope. Adjustment of the rotational direction of the length-measuring tool is difficult after the tool is passed through the endoscope. It is often required to repeatedly insert and remove the length-measuring tool into and out of the forceps channel of the endoscope until the rotational direction of the tool is acceptable.